Low-water alarm for boilers



Nov. 10, 1925.

W. M A. BARBOUR LOW WATER ALARM FOR som'sns Filed April 16. 1924 INVENTOR WITNESSES A TTORNEYS Patented Nov. 10, 1925.

NITE D S TA WILLIAM MAGALLASIER. BARBOUR, OF BOANOKE, VIRGINIA.

LOW-WATER ALARM FOR BOILERS.

Application filed" April 16, 1924. Serial No. 707,011.

To allwhom it may concern- .1

Be it known that I, Tr-Lemar M. Bnnnorm, a citizen of the United States,residing at Roanoke, in the county of Roanoke, State of Virginia, haveinvented certain new and useful Improvements in Low-VVa.ter Alarms forBoilers, of. which the following is a specification.

My invention is a low water alarm for steam. boilers, and it consistsinthe com-bi.- natirons, constructions, and arrangements hereindescribed and claimed.

An object of the invention is to provide a simple and reliable devicewhich is adapted for attachment to a steam boiler of substantiallyconventional construction and which is adapted to be actuated when thewater within the boiler falls to a definite level to give anaudiblesignal.

A further object of the invention is to provide an attachmentof thecharacter described which willnot interfere with the op oration of theboiler to which it is applied in an ordinary manner and which isthoroughly practical commercially.

Other objects and advantages will be apparent from the followingdescription, considered in conjunction with the accompanying drawings,in which Figure 1 is a longitudinal section: through a portion of asteam boiler and through an attachment embodying the invention withwhich the boiler is equipped,

Figure 2 is a plan view of the attachment with the signal alarm thereofomitted,

Figure 3' is a transverse vertical section through a portion of theupper wall of the boiler and through the attachment, the view beingtaken. substantially on the line 33 of Figure 1, with the signal alarm.omitted,

Figure 4 is a perspective view showing a valve and valve stemconstruction which is comprised in the device, and

Figure 5 is a relatively enlarged section along the line 55 of Figure 4.

In Figure 1, the numeral 1 designates a steam boiler generally. Only aportion of the boiler is shown. As is usual, the boiler is provided witha water chamber 2 which extends below the level of the crown sheet 3 forthe fire-box 4- of the boiler. It, of course, is desirable that means beprovided for apprising an interested person that the level of waterwithin the chamber 2 of the boiler is relatively low since otherwise thecontinued operation of the boiler without an additional quantity ofwater being supplied thereto may result in injury to the-boiler and tothe structure adjacent thereto. My invention contemplates the: provisionof means which will act automatically when the water within the boilerfalls to a definite level to sound an audible alarm.

In carrying out my invention, I provide a box-like casing 5 which issupported upon the boiler top and which defines a chamber 6. The chamber6 has communication with the water chamber 2' of the boiler through adrain pipe 7 which opens at its upper end through the bottom of thecasing 5 and depends within the water chamber 2 below the level of thecrown sheet 3. The chamber 6 also has communication with the chamber 2through a pipe 8 which extends vertically through the bottom of thecasingand terminates at its upper end; adjacent to but short of the topwall of the casing 5. The pipe 8 depends within the water chamber 2 andterminates at its lower end at a slight distance above the level of thecrownsheet 3.

The chamber 6 serves as a. float chamber. A float 9 is supported:therein by being at tached pivotallyto one end, of a float lever 10which is pivotally supported at its other end on a horizontal pivotelement 11 which is carried by lugs 12 depending from: the top of thecasing 5 adjacent to one end of the latter. The float 9 thus is adaptedto move vertically within the chamber 6" in accordance with the rise andfall of liquid therein. A vertical guide 13 depend-s from the top'of thecasing 55- and has a vertical slot 14 in which the floatarm 10 may move,the engagement of the guide 13 with the float arm being adjacent to thefree end of the latter.

The top of the casing 5 is provided with a threaded opening 15 in whichis screwed the lower end portion of a tubular valve casing 16. The boreof the valve casing 16 is reduced in diameter adjacent to its lower end,as at 17, to rather closely engage with a longitudinally slotted valvestem 18 which extends slidably therethrough. The portion of the valvecasing that is reduced in inner diameter is fashioned at its lower end,as at 19, to provide a seat for a downwardly opening tapering valve disc20. The stem 18 extends through the bor of a tubular boss 21 which isupstanding from the valve casing and the upper end portion of the valvestem carries a nut 22 which is in threaded engagement therewith. Anexpansion spring 23 is arranged on the tubular boss 21'be- 'ward untilthe valve has been moved against the seat therefor and to position toprevent flow of fluid from the chamber 6 into the valve chamber 16.. I i

I The valve 20 has apendent axial extension 24 which is enlarged andfashioned in loop format the lower end thereof, as indicated at 25., Thefloat arm 10 extends through V V 16 to'the whistle'28 and W111 cause thelatter 5 the loop and engageswith the lower "end of the latter 111 suchmanner as to force the valve 20 downward and away fronrjits seat whenthe float 9 is in lowered position, as illustrated in Figure 1. r

. The valve casing 16 is provided"with a tubular lateral'outlet 26adapted for connection with the-conduit 27leading to a whistle28 orother suitable signal of known type of construction and adapted to befactuated when pressure fluid is supplied thereto. i

A by-pass conduit 29 may connect the upper part of the float chamber 6with the upper part of the water chamber 2 0 1 the boiler and may beprovided with a valve 30 of ordinary construction. i

l I threaded plugs,fas indicated at 81.

From the foregoing description of the various parts of the device, theoperation thereof Wlll bereadily understood; Let us assume that thewater chamber 2 of the end of the pipe 8 andthe valve 30 isclosed; Thesteam pressureVwithin the boiler will have caused water to rise throughthe pipes boiler isfilled to a level above 'theflower 7 and Sand toflow=into the float chamber depends from the valve 20 so that thespring; 23 will bepermittedto function to return the valve 20to closedposition."'VVhenthe level of the water within the chamber? falls belowth -lower end of the pipe 8, the

pressure fluid from the boiler will pass through the pipe 8 into the'float chamber and the, pressure within the float chamber and the boilerwill be equalized and, therefore, water will be drained from thechamwater level within th float chamber, thereby causing movement of thevalve 20 from its seat; The pressure fluid Within the float 6,-then willescape through the valve casing to be actuated, whereby an audiblesignal will be given. I r 1 Obviously, my invention is susceptibleofembodiment in forms other thanthat which is'illustrated in theaccompanying drawings, and I, therefore, consider as my own allmodifications and adaptations that fairly fall Within the scope of theappended claim.'

The by-pass 29 and valve 30 are provided to facilitate the testing ofthe device.

The combination with a boiler, of a casing superimposed-on the boiler,said casing having an outlet adapted for connection with a whistle, adownwardly opening valve controlling said outlet and spring-pressedtoward closed position, a float, means adapted to be actuated ondownward movement of said float to move said valve from closed posltlon,a pipe establishing"communication between the water chamber of theboiler an-dthe interior of said casing, said pipe terminating at itsupper end ata considerable distance above the level of the bottom of thecasing and terminating at'its lower end slightly abov the'level of thecrown sheet of the boiler, a second pipe opening at its upper endthrough the bottom of the casing and depending within the water chamberto terminate at its lower end below the level of the crown sheet of theboiler. and a valved by-pass conduit connecting the upper part of saidcasing with the upper part of said boiler. p j

I WILLIAM MacALLASTER HARBOUR.

